I guess I have in mind not just the fact that nudist/naturist groups state up front that they are not into sexual exhibitionism or swinging or whatever, which makes sense, but their explicit avowals that "it's totally non-sexual; there's nothing sexual about it -- that's not what it's about, etc. etc." I think we can differentiate between declarations of purpose that state "We are not a perv/swinger organization," which is credible and also (as you suggested) lends credibility, from those that state, in so many words, "We are not about looking at each other naked; there is no sexual overtone to our gatherings at all; and it's totally non-sexual to be nude the way we are!!!" -- which I meant to question.